Oct 24 (Reuters) - Chili's Grill & Bar parent Brinker International Inc on Wednesday said a cool-down in sales at established restaurants was stretching into the current quarter, sending its shares down more than 10 percent.

The Dallas-based company, which also owns the Maggiano's Little Italy chain, also reported a fiscal first-quarter profit that just missed Wall Street's estimate and issued a second-quarter earnings forecast below analysts' target.

Brinker's results came just days after industry leaders McDonald's Corp and Chipotle Mexican Grill Inc turned in disappointing results and dragged down the restaurant sector.

``Late in the first quarter and even into the current quarter, (sales) trends softened significantly across the category,'' Wyman Roberts, Chili's president said on a conference call with analysts.

Brinker's net income rose 18 percent to $27.9 million, or 36 cents per share, for the fiscal first quarter that ended Sept. 26.

Excluding a gain related to royalty revenues, the company earned 37 cents per share, missing Wall Street's average estimate by a penny, according to Thomson Reuters I/B/E/S.

Restaurant operating margins improved by about 150 basis points to 14.6 percent from 13.1 percent a year earlier, helped by projects that have streamlined staffing and upgraded kitchen and point of sale systems.

Revenue rose just more than 2 percent to $683.5 million.

Sales at restaurants open at least 18 months rose 2.8 percent at Chili's and 0.9 percent at Maggiano's during the quarter. Analysts polled by Consensus Metrix were looking for a 2.3 percent rise at Chili's and a gain of 2.4 percent at Maggiano's.